If you have more than one video card installed, Elcomsoft Distributed Password Recovery can use up to 32 dedicated video cards at the same time. Depending on which video card is installed and what type of encryption we are dealing with, one can expect the recovery speed to raise some 50 to 250 times faster compared to CPU-only benchmarks. Featuring several hundred GPU cores, a single video card can deliver the speed far exceeding the metrics of a high-end CPU. GPU acceleration offloads computational-intensive calculations from the computer’s CPU onto the highly scalable video cards. This is how we arrived to the idea of using video cards to accelerate the recovery. High-end and mid-range video cards manufactured by NVIDIA and AMD can render complex 3D scenes in real time something that a bare CPU would struggle with. Additional computation power is urgently needed to break passwords in reasonable time.Īt the same time, today’s power-hungry video cards ship hundreds of dedicated high-performance cores working in parallel. With hundreds of thousands or even millions hash iterations used to slow down the recovery, attacks running on a CPU alone can only break the simplest passwords. What is GPU acceleration and how does it work?Īs demonstrated earlier, the speed of a single CPU is not enough to break many types of passwords. Particularly important is the fact that all common data protection algorithms only use the system’s central processor (CPU) when it comes to verifying the password. As a result, manufacturers profile their data protection algorithms so that the data can be accessed in about 0.3 to 1 second on an average (or below-average) system. Manufacturers of data protection tools cannot increase the protection indefinitely there is only so much time the user is willing to wait for a password-protected document to open or an encrypted volume to mount. However, there is light at the end of the tunnel. This is often achieved by increasing the number of rounds (recursive calculations of a hash function) that is used when processing the user’s input and turning it into an encryption key. While makers of password recovery tools are trying to break password as fast as possible by trying increasing numbers of password combinations per second, makers of data encryption tools are doing exactly the opposite in order to slow down attacks. Recovering the original password is often the only way to access the data. The majority of plain text passwords have significantly lower entropy compared to 256-bit or even 128-bit media encryption leys. The media encryption key itself is either directly produced from the user’s text-based password or encrypted with the user’s text-based password. With the binary media encryption key out of the reach of today’s brute force algorithms, one must target something else instead. The encryption algorithm protects data with a 128-bit or 256-bit Media Encryption Key (MEK, sometimes also referred as a Data Encryption Key, or DEK), which is long enough to make brute-force attacks out of the question. Most types of data protection today implement encryption. If you have not yet read the “What is password recovery and how it is different from password cracking” article, you may want to review it for the basic theory of password cracking. How much faster, exactly, depends on several things: the type of the video card (more on that later), the number of video cards installed, and the algorithm that was used to convert the password into a binary 128-bit or 256-bit encryption key. Literally, we need GPU acceleration to break passwords faster. In this article, I’ll discuss the two acceleration techniques in more detail. In that article, I briefly mentioned GPU acceleration and distributed attacks as methods to speed up the recovery. The November article “What is password recovery and how it is different from password cracking” explains the differences between instantly accessing protected information and attempting to break the original plain-text password. Modern encryption tools employ strong encryption with multiple hash iterations, making passwords extremely difficult to break.
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